The present invention relates to the production of boil-in-bag preparations and particularly to a process for the production of dimensionally stable, sliceable, starch-containing products, such as dumplings, in a boil-in-bag package. The process comprises at least partially gelatinizing the starch-containing starting material, freezing it, comminuting the frozen starch sponge, thawing, dewatering it by pressing and/or drying, and packaging it in a boil-in-bag package. The fill quantity and the remaining head space in the bag are dimensioned in such a way that the cooked product completely fills the boil-in-bag package and a dimensionally stable, sliceable, edible product results from the pressure of the hydrated contents of the bag against the bag wall.
Boil-in-bag preparations have increasingly been gaining importance in recent decades because of their convenience. This applies particularly to rice products and dumpling products such as potato dumplings and bread dumplings. Despite the different character of these products, they have one feature in common: both absorb large amounts of water in preparation, particularly when boiled, i.e. they swell and occasionally experience increases in volume.
In the case of rice, and other cereal products such as farina and pearl barley, this swelling is taken into account in traditional cooking, by beginning the cooking operation with a considerable excess of water or liquid. Also in the case of less coarse grained products such as rice, as the swelling increases, the uniform distribution and thus availability of the water required for further swelling must be ensured by occasional stirring. This type of preparation is relatively complex, and requires a certain amount of supervision, without which the preparation does not, or only partially, succeeds. Moreover, this process poses difficulties in the case of very large portions, and also very small portions.
Because of the current trend towards convenience (which is equivalent to simpler preparation in this case) and towards progressively smaller households, there is a requirement for dependable and simple preparation of such products in portions. A preparation which meets this requirement is the boil-in-bag preparation of rice which is limited to parboiled rice. To date, farina, pearl barley and the like have not been able to be prepared in boil-in-bag packages, which have proved useful for rice. This is because the great volume increase on swelling means that only a little may be packaged in the bag, and also because uniform, homogeneous swelling and distribution in the bag cannot be ensured. Although boil-in-bag rice essentially achieves good and uniform rehydration, when dealing with dumpling products a defined shape must also be ensured.
Against this background, the development of easy to use dumpling products has been achieved in two steps. The first step was the development of completely formulated dry products which, after preparation with the appropriate amount of liquid (usually by hand), only had to be shaped and cooked. The introduction of the boil-in-bag package was step two, thereby removing the shaping of the dough from the consumer or chef. In order to achieve this result, a boiling-resistant, boil-in-bag package had to be developed, and the perforation thereof had to be arranged in such a way that rapid penetration of the water is ensured, while no excessively large cooking losses, nor blockage of the pores occurred.
Even more important than the development of a suitable film, was the adaptation of the formulation or the selection and development of suitable ingredients, since the rapid, complete and uniform penetration of the liquid entering through the bag pores was required since the conventional mixing or kneading of the dough could not carried out in this case. A mixture suitable for the boil-in-bag package must absorb sufficient water in order to ensure the swelling and filling of the bag to give the desired shape and ensure cooking, but must not swell too rapidly and too vigorously until all the liquid has entered through the pores.
A number of the conventional ingredients posed few problems in this respect, such as, for example, bread crumbs and dried potato flour, which are distinguished by a relatively slow water absorption, have a porous structure as such and, because of their piece size, give a lose, macroporous bulk. Although the bread dumpling mass, porous and in pieces per se, does bind water to a considerable extent on boiling, it is comparatively, dimensionally stable and swells comparatively little. Bread dumplings can therefore also be prepared without problem in relatively large, cylindrical boil-in-bag packages.
However, other traditional formulation components such as mashed potato powder and swelling starches had to be appropriately modified because of their rapid water absorption and high swelling characteristics. One modification, which has proved to be useful in this respect, was the production of so-called pellets. In the production of pellets, the raw material in question (for example potatoes or rice) is comminuted, as described, for example, in DE 37 16 467, in well-hydrated form (usually after precooking) with the aid of an extruder, mincer or the like and, generally with the addition of other ingredients, such as binders, is shaped to form strands of the desired diameter. These are then cut up into slices of equal thickness (pellets) with the aid of a suitable cutter, and are dried. Pellets produced in this manner have a certain, albeit low, porosity which ensures the penetration of the liquid into the pellet, and they ensure, as a result of their size (3-5 mm) and their generally lens-like shape, an open and loose bulk. As a result of this adaptation of the formulation components to the specific requirements in the boil-in-bag package, goods products which are reliable and uniform, are now available.
However, there continues to be problems with rice and cereal products, especially when these are to be produced in a highly specific shape, e.g. a sliceable, cylindrical roll, the boil-in-bag package (as is desirable for the production of decorative accompaniments, especially in catering or restaurants). There are also difficulties with potato dumplings when these are prepared in relatively large boil-in-bag packages, as is demanded in catering. Obviously, the measures described above are not sufficient to ensure rapid and uniform rehydration. Dry, insufficiently hydrated, uncooked portions are frequently found in the finished product and, if the access of liquid into the interior is particularly inadequate, cavities or holes are also found.
A fundamental problem with both product groups is that the products or mixtures when in dry form only partially fill the boil-in-bag package, but completely fill it after corresponding swelling which takes place predominantly during the cooking operation.
This leads to uneven water absorption and thus inhomogeneous products, and also, with the then very high head space volume, to a twisting of the bag and thus to an undesirable deformation of the product.
Therefore, there is a requirement for ingredients which are highly porous, rapidly absorb water, can be produced in varying sizes, swell comparatively little, are relatively dimensionally stable and simultaneously bind water during cooking for preparation in boil-in-bag packages, particularly for preparation in relatively large boil-in-bag packages. Surprisingly, it has now been found that ingredients which are produced by the so-called "sponge technique" ideally satisfy these requirements, especially in combination with previously used ingredients.
This technique (used for example, in DE 29 38 594 for the production of a tomato product which is dry after reconstitution) starch-containing ingredients are first frozen, then the liquid released from the sponge formed by the retrogradation of the starch is separated off in an appropriate manner and the product is dried. With the aid of this technique, the above described problems in the preparation in boil-in-bag packages are surprisingly overcome.